This subterranean structure was commissioned by Emperor Justinian and built in 542. The largest surviving Byzantine cistern in İstanbul, it was constructed using 336 columns, many of which were salvaged from ruined temples and feature fine carved capitals.
It was originally known as the Basilica Cistern because it lay underneath the Stoa Basilica, one of the great squares on the first hill of the city of Byzantium. Designed to service the Great Palace and surrounding buildings, it was able to store up to 80,000 cu meters of water delivered via 20km of aqueducts from a reservoir near the Black Sea. It was closed when the Byzantine emperors relocated from the Great Palace.
Forgotten by the city authorities, it was rediscovered in 1545, when scholar Petrus Gyllius was researching Byzantine antiquities in the city and was told by local residents that they were able to miraculously obtain water by lowering buckets into a dark space below their basement floors. Some were even catching fish this way. Intrigued, Gyllius explored the neighbourhood and finally accessed the cistern through one of the basements (http://www.lonelyplanet.com/turkey/istanbul/sights/other/basilica-cistern#ixzz3HHq0aEYc)
We like the moody atmosphere of the photos we've taken; most of them require no additional explanation to that given above.